Pre-Operative Risk Assessment Emily Clay, MD, FAAFP Family Medicine Residency Faculty Martin Army Community Hospital, Ft. Benning USAFP Presentation April 2011 Objectives Understand that we are not “clearing” a patient for surgery Recommendations for evaluation prior to surgery Algorithm for risk-stratifying patients Risk-stratification of surgeries Medical recommendations Case Dr. X’s nurse at the Columbus Orthopedics clinic has paged you asking that your 89 yo male patient Jim Smith scheduled for right hip arthroplasty in 3 days be cleared for surgery. What is your response? How do you quickly assess this patient’s risks? What tests and/or meds do you order? Case, continued PMH: MI 1 yr ago- received antithrombolytics with resolution of symptoms No tobacco history, or h/o CVA or DM. Normal EF and renal function. Walks 2 miles in the morning for years, now limited last 4 months by hip pain Meds: HCTZ 25mg daily, Zocor 40mg daily, Aspirin 81mg daily, also ran out of Atenolol 25mg daily 2 weeks ago. Case, continued Mr Smith’s vitals: 157/92, HR 70s, normal temp, RR, O2 sat. BMI 25. Normal physical exam EKG with Q waves inferiorly Is the surgery an emergency? If condition requiring surgery is acutely life- threatening, then go straight to surgery, without further evaluation… If surgery is not an emergency… 1- Assess patient risk factors for perioperative morbidity and mortality 2- Assess surgical risk This info will help determine: – Need for diagnostic testing – Measures to prepare higher risk patients for surgery Preoperative outpatient medical evaluation – May decrease length of hospital stay – May minimize postponed or cancelled surgeries. Preoperative History PMH, PSH, prior complications of surgery, anesthesia Medication Reconciliation, Allergy Review Immunization Status Smoking, alcohol, drug use (stop smoking >8 weeks prior to surgery) Social support (need any assistance after hospital stay, even a ride home from the hospital?) Preoperative Physical Exam Vitals- height, weight, BMI, BP, HR, O2 sat, RR, temp, pain scale. Cardiac exam: murmurs, gallops, signs of CHF, irregular rhythms, etc. Lung exam: signs of acute or chronic pulmonary disease. Signs of malnutrition Mental status exam (baseline) Summary of Recommended Preoperative Tests (pending H&P findings) Healthy < age 40: CBC, Urine HCG Healthy > age 40: Add EKG and blood glucose Recommended Preoperative Tests for Patients with Elevated Cardiovascular Risk Factors EKG, CXR, CBC, CHEM 7. Also: – If recent MI < 6 weeks, unstable angina, decompensated CHF, significant arrhythmias, severe valvular disease: CARDIOLOGY CONSULT – Previous MI> 6 weeks, mild stable angina, compensated CHF, DM: STRESS TEST, +/- ECHO – Rhythm other than NSR, h/o abnl EKG, h/o CVA, advanced age, or low functional capacity: STRESS TEST Summary of Recommended Preoperative Tests for Patients with Pulmonary Risk Factors CXR, CBC, CHEM, EKG, provide instructions for incentive spirometry or deep breathing exercises. – Asthma: PFTs or PEAK FLOW – COPD: PFT, ABG baseline – Cough, dyspnea: Evaluate etiology – Smoking: Counsel on tobacco cessation 8 weeks prior to procedure. Summary of Recommended Preoperative Tests for Patients with Other Risk Factors Obesity or Obstructive Sleep Apnea: Instruct patients on Incentive Spirometry or deep- breathing exercises Abdominal or thoracic surgery: Instruct patients on IS or deep-breathing Malnutrition: Labs based on primary disease (Cancers, HIV, etc), plus albumin (<3.2) and lymphocyte count (<3000). – Consider postponing surgery if severe – Provide nutritional supplementation pre- and post-op Cardiovascular Disease Affects 25% of the US population Leading cause of death in the US > 60% of CV deaths due to coronary disease Perioperative Risk 20-40% of patients at high risk of cardiac- related morbidity will develop myocardial ischemia perioperatively Of 27 million patients undergoing anesthesia annually in the U.S., 0.2% or 50,000 will have a perioperative MI. Fleisher LA, Eagle KA. Clinical Practice. Lowering Cardiac risk in noncardiac surgery. N Eng J Med 2001; 345;1677-82 Perioperative Cardiac Complications Approx 50% are due to postoperative ischemia or CHF Highest in first 48 hrs after surgery Ischemia may be silent in 90% of cases Patient risk stratification Clinical Predictors of Increased Perioperative Cardiovascular Risk MAJOR RISK: - Unstable coronary syndromes (acute MI, severe angina) - Decompensated heart failure - Significant arrhythmias - Severe valvular disease Clinical Predictors of Increased Perioperative Cardiovascular Risk INTERMEDIATE RISK: - Mild angina - Previous MI by history or pathologic Q waves on EKG - Compensated or prior heart failure - Diabetes mellitus (esp if on insulin) - Renal insufficiency Clinical Predictors of Increased Perioperative Cardiovascular MINOR RISK: Risk - Advanced age (>75 yrs) - Abnormal EKG results (LVH, LBBB, ST-T wave changes) - Rhythm other than sinus (A fib) - Low functional capacity (inability to climb one flight of stairs w/ bag of groceries) - H/o CVA or uncontrolled systemic HTN Surgical risk stratification Procedures at HIGH risk for cardiac death and nonfatal MI (>5% chance of cardiac event) - Emergent major operations, esp in pts >75 - Aortic and other major vascular surgery - Peripheral vascular surgery - Anticipated prolonged surgical procedure associated with large fluid shifts or blood loss Procedures at INTERMEDIATE risk for cardiac death and nonfatal MI (1-5% chance of cardiac event) - Carotid endarterectomy - Head and neck surgery - Interperitoneal and intrathoracic surgery - Orthopedic surgery - Prostate surgery Procedures at LOW risk for cardiac death and nonfatal MI (<1% chance of cardiac event) - Endoscopic procedures - Superficial procedures - Cataract surgery - Breast surgery TESTING and EVALUATION prior to surgery Goals of Perioperative Testing - To measure functional capacity - To identify the presence of myocardial ischemia or cardiac arrythmias - To estimate cardiac risk Positive predictive value -Proportion of patients with positive test results who are correctly diagnosed -Precision rate Negative predictive value -Proportion of patients with a negative test result who are correctly diagnosed. - High NPV = when the test yields a negative result, it is uncommon that the result should have been positive Exercise Tolerance - Important predictor of perioperative risk and need for invasive monitoring - Excellent exercise tolerance, even if pt has stable angina, suggests that the myocardium can be stressed without becoming dysfunctional. - Suggested likelihood of complication inversely proportional to # of blocks that can be walked or flights of stairs climbed. Exercise/ Stress Testing Reserved for moderate to high risk patients undergoing moderate to high risk surgery If testing has been done within 6 months of surgery, not necessary to repeat (unless new symptoms) – Same if revascularization procedure done within 6 months, if no new symptoms Myocardial Perfusion Imaging For patients undergoing Vascular Surgery: - Positive predictive value (PPV) for ischemia of 4-20% - NPV 95-100% For patients undergoing NON-Vascular Surgery: - PPV for ischemia 8-67% - NPV 98-100% Dobutamine stress echocardiogram testing PPV for ischemia 10-24% NPV for ischemia 98-100% Eagle KA, Berber PB, Calkins H, Chaitman BR, Ewy GA, Feischmann KE, et al. ACC/AHA guidelines update for perioperative cardiovascular evaluation for noncardiac surgery- an executive summary: a report of the ACC/ AHA Task Force on Practice Guidelines. J Am Coll Cardiol 2002; 39:542-53. Coronary Artery Revascularization Prophylaxis (CARP) Study- published Nov2004 - 5959 pts w/ CAD risk factors undergoing elective major vascular surgery assigned to 2 groups - Received coronary art revascularization (i.e. percutaneous coronary intervention or bypass surgery) before surgery - Received no revascularization prior to surgery - Study excluded pts with EF<20%, Left main coronary artery stenosis, or severe aortic stenosis CARP Study Tested the hypothesis that coronary artery revascularization prior to elective surgery improves long-term survival. Multicenter, randomized, controlled, cooperative trial involving subjects from 18 Veterans Affairs Medical Centers. CARP Study Outcome 30 days post-op: 12% pts in revascularization group and 14% pts in non-revascularization group suffered post-op MI 3 years post-op: 22% mortality in revascularization group and 23% in non-revascularization group CONCLUSION: Coronary artery revascularization before elective vascular surgery on moderate-risk patients does NOT significantly alter the long- term outcome and cannot be recommended. Other Methods to Assess Cardiac Risk - Goldman criteria (1977) - Detsky’s clinical risk index (1986) - Lee’s revised cardiac risk index (1999) Lee’s Revised Cardiac Risk Index Clinical Variable - High-risk surgery= 1 point - Coronary artery disease= 1 point - CHF= 1 point - H/o CVA= 1 point - Insulin tx for diabetes= 1 point - Preop serum creatinine> 2.0mg/dl= 1 point Lee TH. Circulation. 1999 Sep 7; 100(10): 1043-9 Lee’s Revised Cardiac Risk Index- Scoring Very Low Risk= 0 points (0.4% risk of complications) Low Risk= 1 point (0.9% risk of complications) Moderate Risk= 2 points (6.6% risk of complications) High Risk= 3+ points (11% risk of complic) Formula on smartphones (Medcalc, etc) Medical Treatment to Reduce Perioperative Risks Meds to Reduce Perioper Risk: Beta Blockers - Studies support the use of perioperative beta blockade to reduce c/v morbidity and mortality only in patients with known cardiovascular disease undergoing vascular surgery and in those already on beta blockers. Beta Blockers - Target heart rate in 60’s perioperatively - Previous studies showed that perioperative beta blockade decreased risk of MI during and after surgery - 2 studies (POISE and DECREASE-IV) - Usefulness less well-established in: - Pts with intermediate or high-risk procedures or vascular surgery who are low or intermediate in cardiac risk factors. - Pts with low cardiac risk not previously on beta blockers POISE Study- 2008 Perioperative Ischemic Evaluation trial Large, randomized, controlled study of 8000 patients from 23 countries, >age 45, increased cardiac risk, having noncardiac surgery. POISE showed: – MI risk was reduced in patients randomized to beta blockers – But they also had a HIGHER risk of stroke and death= net harm – Lancet, May 2008 POISE Study- 2008 For every 1000 patients treated, metoprolol CR would prevent 15 MIs, but there would be an excess of 8 deaths and 5 severe disabling strokes. POISE Did not address patients already on beta blockers 2009 AHA/ACC guidelines taskforce on beta blockade agree that these patients should remain on their beta blockers through surgery Meds to Reduce Perioper Risk: Statins Act via multiple mechanisms to improve atherosclerotic plaque stability and to inhibit leukocyte adhesion Current evidence provides support for statins in patients at high risk of perioperative mortality. Statin Recommendations Class I: For patients currently taking statins and scheduled for noncardiac surgery, statins should be continued (Level of Evidence: B) Class Iia: For patients undergoing vascular surgery with or without clinical risk factors, statin use is reasonable. (Level of Evidence: B) Class Iib: For patients with at least 1 clinical risk factor who are undergoing intermediate- risk procedures, statins may be considered. (Level of Evidence: C) Meds to Reduce Perioper Risk: Alpha2-Agonists -Number of studies suggest a reduction in the incidence of perioperative myocardial ischemia in patients undergoing vascular surgery. - One recent study rec’s clonidine pill or patch started on morning prior to surgery and continued for 4 days postoperatively. Meds to Reduce Perioper Risk: Calcium Channel Blockers and Nitrates - To date, no evidence that there are additional benefits from using these meds perioperatively to reduce risk. Antiplatelet Therapy Continue aspirin preoperatively when used as secondary prevention of cardiovascuar disease & stroke Continue plavix after stent or MI for recommended timeframes due to risk for coronary stenosis Biondi-Zoccai GG, Lotrionte M, Agostoni P, et al. A systematic review and meta-analysis on the hazards of discontinuing or not adhering to aspirin among 50,279 patients at risk for coronary artery disease. Eur Heart J. 2006;27(22):2667-2674. Antiplatelet Therapy Risk of CV events when stopping antiplatelet therapy is higher than the risk of surgical bleeding when upholding them Elective operations should be delayed beyond dual antiplatelet therapy Operations on dual antiplatelet therapy should be continued without operation ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines Types of Anesthesia Anesthesiologist to choose the type of anesthesia General & epidural anesthesia may not differ significantly in rates of perioperative cardiac complications (studies conflict) Key Recommendations for Practice Beta blockers should be considered perioperatively to patients with known ischemic heart disease undergoing vascular surgery or who have previously taken beta blockers. BB are not recommended for patients with low to moderate risk of perioperative cardiovascular complications (Class B rec) Key Recommendations for Practice, continued Statin use is assoc w/ reduction in perioperative risk in patients with preexisting CAD, although randomized trial data are lacking (Class B rec) Alpha2-agonists (clonidine) are a possible alternative to beta blockers to reduce perioperative risk of cardiac complications in high-risk patients (Class B rec) Case Discussion Hip arthroplasty= intermediate risk surgery Lee revised cardiac risk index= 1 point CAD (LOW RISK for perioperative cardiac event) Good functional status, so decided that stress testing not necessary Refill atenolol beta blockade that pt was on previously Continue statin therapy Continue aspirin therapy References 1. American College of Cardiology/American Heart Association (ACC/AHA) Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery, 1996, updated 2002 and 2007. 2. “Preparation of the Cardiac Patient for Noncardiac Surgery,” Flood and Fleisher, American Family Physician. 2007 Mar 1;75(5):656-665 3. “Preoperative Cardiac Risk Assessment,” Karnath, American Family Physician. 2002 Nov 15;66(10):1889-1897 4. “Preoperative Evaluation,” King, American Family Physician, July 15, 2000. 5. “Cardiovascular Evaluation and Management of Severely Obese Patients undergoing surgery: A science advisory from the American Heart Association,” Poirier, et al, June 2009. 6. “Cost-effective Preoperative Evaluation and Testing,” Fischer, American College of Chest Physicians, 1999; 115:96S-100S. 7. “Perioperative Antiplatelet Therapy,” Chassot, Marcucci, et al, American Family Physician. 2010 Dec 15;82(12):1484-1489. 8. “Safety of short-term discontinuation of antiplatelet therapy in patients with drug- eluting stents,” Eisenberg MJ, Richard PR, Libersan D, Filion KB . Circulation. 2009;119(12):1634-1642 9. Burger W, Chemnitius JM, Kneissl GD, Rücker G. Low-dose aspirin for secondary cardiovascular prevention - cardiovascular risks after its perioperative withdrawal versus bleeding risks with its continuation - review and meta-analysis. J Intern Med. 2005;257(5):399-414.